Audio: no switch between line level / mic level?

[Eugene Presley]

Well James,


Looks like you worked with a different XL1s then mine, and some other belgians collegues.

Of course you can swith between mic & line in the menu, but when I'm setting the menu on line and recieving sound from a Sounddevices Mixpré, audio is distorted. Tried everything, also the att20-function, nothing worked.

[Don Palomaki]

The MA-100 is NOT designd to deal with line level inputs. It will saturate and clip at around -7 dBV input level. It's impedance is about 600 ohms. It is designd for use with MIC level sources with a 600 ohm (or lower) output impedance. Same probably applies to the MA-200.

Pro audio gear typically has a line level around a nominal +4 dBU, and nominally 600 ohm in/output impedance. Output impedances often are lower.

Consumer gear unbalanced line level is about -10 dBV, and typically on the order of 10k ohm input impedance or higher. Today output impedance is typically on the order of 2000 ohms, but that varies widely and is usually not an issue for consumer gear.

With modern solid state gear, for audio what matters is the that the output impedance of the audio source should not be higher than the input impedance of the camcorder, etc. Being lower is OK.

Many mixers have mic level output on the order of -30 dBV, which nominally corresponds to the Canon MIC ATT level. The tape output RCA jacks on many mixers often correspond to consumer line level.

On the XL1 the RCA inputs (Audio 1 and Audfio 2) could be set for MIC, MIC ATT and (consumer) Line level input sensitivity. The input impedance changed corrspondingly. MIC ATT and Line level inputs selection gave the best noise floor. (I do not have corresponding info for the about the XL12.)

If folks do not understand the basic of sound and the capabilities of their gear they should seek competent assistance from someone who understands audio and the gear in question. Responses in web forums may not always be the best source of advice - you can't always determine the competence of the responders with respect to your problem and gear, or whether they have an agenda of their own.

Balanced line input capability is a nice to have, but if one is arouund line level output infrastructure, adding a 40 dB pad is a minor issue - should be one in everyones audio kit any way. Omitting it maybe a means of avoiding B2B issues with Sony, Panasonic, etc.

[James Emory]

Oops. Eugene, your post said the XL-1:

"This is absolutly unbelievable, what a big mistake. I know here in Belgium a lot of XL1-owners modificated their MA-200, to be able to switch between mic/line. They turned their camera's in a professionale video-repair centre, and some custum made switches were added to the MA-200."

Maybe it's different with s.

_____________________________

Don, I heard that! I am not an audio person, I just know that we do it the way I described and it works great. I don't know what kind of output that is coming from the field mixer mic / line each time we've done it. But it has been done with 3 different mixers/operators perfectly. I'll be sure to find out next time. I know that you know what's going on and I'm listening. Thanks for the info.

[Marco Leavitt]

I have that Audio-Technica attenuator that was mentioned earlier by the way. It's a handy gadget, but its size can be kind of awkward, and I'm not sure that 30 dbs would be enough to lower the signal to mic level. SoundDevices makes a series of attenuating cables designed to do this, but I think they may unbalance the signal.

[Aaron Koolen]

Line level seems to be a gimme these days on cameras with XLR inputs. It's just a standard thing you chuck on a camera - like a power switch (OK, not quiet that obvious ;) ). To leave one out is just stupid.

Aaron

[Lauri Kettunen]

<<<-- Originally posted by Don Palomaki : seek competent assistance from someone who understands audio and the gear in question. -->>>

Right, I agree with Don. To complete what he said, the point is that an audio signal in the cable is not like water in a pipe. When the audio cable is connected to some other device, if the impedances do not macth properly, the signal is reflected back to the cable and/or badly degraded. That's why all this talk of impedances have practical significance.

Thus, the output impedance of the mics one uses is meaningful. There are not that many cheap microphones whose output is less than 600 ohms. Using a one with higher impedance and if such a mic with a long cable results likely in a weak signal signal with damped higher frequencies.

High quality audio equipments with low noise cost easily the price of Xl1s/XL2. The prices of single components, like of the 40dB pads, vary also a lot, and typically, in the end of the day, the more you pay, the less you tend to get noise.

Before blaiming Canon for making a silly mistake of leaving out the XLR line inputs, it may be wortwhile to consider the issue the other way around. What about if Canon did not want to bluff the users with the cheapiest solution, but instead invested the money to improve the quality of the AD (analog-digital) converters? I would personally prefer proper AD converters, because if they are poor, there is not much one is able to do to improve the sound quality.

[Aaron Koolen]

I guess we can make whatever excuses we want for Canon regarding all the things they've done (or not done) to the Xl2 but I consider no line in to be a brain dead thing to leave out.

It really strikes me as strange that the people who currently have them and have been sharing their insights will defend all these things that some of us are saying are stupid. Come on guys, are you *really* totally happy with it?

To me image is important of course, but usability is VERY important. The extra time taken to adjust exposures, and attach XLR adapters like on older cams like my XM2, or fiddle with settings etc, is important and I'd gladly pay more for these things to become more convenient. The image stuff has been done, Panasonic did it years ago - old hat - next!. The tweaks and adjustments and niceties is what makes or breaks it for me and where I was hoping Canon would put most of their effort.

Aaron

[Lauri Kettunen]

<<<-- Originally posted by Aaron Koolen : Come on guys, are you *really* totally happy with it? -->>>

Putting it this way, the answer is obviously "no".

But, I would neither appreciate a "fake" XLR line input. I mean, as Barry said, you can get an in-line pad for $45, and they could have incorporated such a thing within the camera body and many would have perhaps been pleased.

Techinally, however, that would have been a dummy choice: One first amplifies the audio signal to line level --creating unavoidably some noise-- with some mixer/preamplifier, then the signal is taken down with a pad, and eventually the signal is amplified once again with the preamplifier within the camera generating , again, more noise. (This is why I don't like to use myself the pads.)

I guess, the audio development team at Canon must have had some upper limit of cost, and within these limits they've done their best. One can't get everything with approx. $5000.

What is nice in the XL2 is that one has now sync out (if I've understood things right). This means, one can sync an external audio device --as high quality as one affords to have-- with the camera and record e.g. multichannel audio for dolby 5.1 surround. In this sense, Canon has thought about the pro-audio needs and provided us with a technical solution for that. If they have been this honest at Canon, my answer to Aaron's question is "yes".

[Aaron Koolen]

Lauri, cameras for years have had line level in - I can't believe for an instant that the decided not to put it in - especially on a "pro' camera - just cause of price. If they did, they are as idiotic as I'm thinking they are.

Also where does it say it has sync out? I haven't come across that yet - that would be nice. But even if they have sync out, it just says to me that Canon don't know their arse from their elbow? What was their market? Low end Filmmaker? High end? Eng? Now I, and posslby mistakingly so, thought it was the same/very similar market as the DVX100, PD170 etc. But making us buy more lenses to get all the manual control, not having line level in, mind numbingly stupid iris contro, is is just rubbing our noses in it IMO.

For full manual lens and B&W viewfinder, adapter for line level balance XLR etc aren't we now talking about the same league as cameras like the Panasonic DVC200 - 1/2" chips, full shoulder mount, full sized 270 odd minutes recording, pro features, manual lens etc etc? Maybe I'm way off in my math but I don't think so..

Aaron

[Greg Milneck]

<<<-- Before blaiming Canon for making a silly mistake of leaving out the XLR line inputs, it may be wortwhile to consider the issue the other way around. What about if Canon did not want to bluff the users with the cheapiest solution, but instead invested the money to improve the quality of the AD (analog-digital) converters? I would personally prefer proper AD converters, because if they are poor, there is not much one is able to do to improve the sound quality. -->>>

This is NOT a silly mistake, this is a a BLUNDER on Canons part. Adding a MIC/LINE switch is not a costly issue. BTW- Canon DID NOT invest the money to improve the quality of the AD converters....where did this come from??

NOTE- There is a very loud hiss on the MIC input, significantly more than on the Sony PD150 which was complained about for years.

Greg,

I was hoping that I would hear some feedback on the audio with the XL2, I appreciate your observations. When I had my XL1 and XL1s, the only way to get less hissier audio was to run my SoundDevices MixPre from the XLR's out of the mixer into the RCA line ins on the camera, I had to have specially made cables with resistors. I would not even use that MA-100, the line ins were better but still hissy. It still didn't match the quality of the DVX100's audio. I don't even have to use a preamp with that camera, I find the audio quality to be excellent with the DVX. So, from your observations, besides adding what looks like a built in MA100, it sounds like Canon has left the audio alone on the XL2. No line in on the XLRs and hissy audio when using the XLRs mic in is another reason why I can't see purchasing the XL2 yet.

[Lauri Kettunen]

Greg, Aaron, You may well be right it's a blunder, and there is no point to argue on that. I just find it hard to believe Canon engineers would be that naive; there must be some reasonable explanation behind their choice. Accordingly, it's hard to believe the Canon audio team did not have an upper limit on the cost of components they were allowed to put in the XL2.

That Sony has better audio than Canon is no surprise, for Sony has been manufacturing low and high level audio equipments for years. Sony's very long experience in audio design and contacts to component manufactures gives them quite a competetive edge.

XL1's MIC input is not the only hissy component, the headphone jacket is as akward.

[Aaron Koolen]

Lauri, I agree no point in arguing and sorry if I sounded like it - I wasn't arguing with you. I'm just frustrated that's all and trying to figure out the reasoning behind it and maybe add a little voice that Canon *may* hear. If enough of us bitch about these things then maybe they will be heard.....ha!

I'm sure Canon could spin us all some bollocks as to why they did it but in the end I think it's fair of us to expect at least some standard features - that competing cams have...and have had for years.

Greg, do you have a GL2 to compare noise levels between the two?

Aaron

[Greg Milneck]

No I dont, but I can get my hands on one. One note on the hiss-
It sound much worse in the headphone while monitoring the recording than it it does when playing back the same recording in a studio environment.

Playback still has the hiss, but much less than you think you have via the headphones.

[Barry Goyette]

Greg/Aaron

I just ran through a series of comparisons with the DVX and xl2. In all situations they produced a freakily similar level of noise.

--when provided with a good level input from an external microphone, neither produced any audible noise.

I disconnected the microphone and turned up the levels (gain), both cameras produced significant hiss at the highest setting...the xl2 substantially more...but...then I plugged the mic back in to find that the xl2 simply has a greater level of gain at its maximum...so I matched the levels of both cameras (bringing the XL2 down to the DVX maximum) and then re-checked the level of hiss with no signal...identical. This is what I would expect from these cameras...and I doubt that the gl2 is far off.

Barry